Field of the Invention
The present invention is related to photodiagnosis and photodynamic treatment.
Background Art
“Genital human papillomavirus (HPV) is the most common sexually transmitted infection (HPVI) in the United States. More than 40 HPV types can infect the genital areas of men and women, including the skin of the penis, vulva (area outside the vagina), and anus, and the linings of the vagina, cervix, and rectum. These types can also infect the lining of the mouth and throat. HPV types are often referred to as ‘low-risk’ (wart-causing) or ‘high-risk’ (cancer-causing), based on whether they put a person at risk for cancer. The International Agency for Research on Cancer found that 13 HPV types can cause cancer of the cervix; one of these types can cause cancers of the vulva, vagina, penis, anus, and certain head and neck cancers. The types of HPV that can cause genital warts are not the same as the types that can cause cancer.” Centers for Disease Control, http://www.cdc.gov/cancer/hpv/basic_info/.
Certain HPV types are highly associated with cervical dysplasia and cervical cancer and are considered to be causative. Walboomers et al., J. Pathology 189:12-19 (1999). Annually, hundreds of thousands of women around the world die of cervical cancer, a condition that affects millions of women, especially those who are economically disadvantaged. Diagnosing and treating HPVI of the cervix and cervical dysplasia in their early stages will lower the incidence of cervical cancer, thus lowering its associated morbidity and mortality.
The current standard for diagnosis is the pathological examination of cervical tissue samples, e.g., the Papanicolaou test or “Pap smear” and biopsy with aid of colposcopy. However, these diagnostic methods require a delay between the time a tissue sample is taken and the time the test results are known. They also require at least one return visit for treatment. Moreover, in disadvantaged populations, these diagnostic methods simply are not available. When and where they are available, biopsies can present patient complications including local inflammation, pain, infection, and/or bleeding. In addition, the accuracy of the pathological examination is dependent on the pathologist's and doctor's training and experience. In addition, HPVI and cervical dysplasia can affect multiple sites of the exocervix and endocervix. Thus, a common problem in the diagnosis and treatment of cervical dysplasia and cancer is the failure to detect and treat all existing lesions.
There are several modalities for the treatment of cervical dysplasia and cancer, most of them involving variable degrees of surgical interventions such as CO2 laser vaporization, cryotherapy, electrocautery, or local excision. Surgical removal of visible lesions is the most commonly modality and may result in patient complications. In addition, an inability to identify all existing lesions allows undetected HPVI and/or dysplasia to evolve into terminal cervical cancer. If the cervical dysplasia progresses to cervical cancer, more extensive surgical procedures are used, typically a hysterectomy and removal of lymph nodes. The entire diseased organ must be removed to assure that all microscopic disease is treated. Since the percentage of these lesions that will advance to a frankly malignant state is unknown and may be a minority of instances, indiscriminate destruction or surgical removal of the entire organ is, in fact, a radical and excessive treatment. For cervical cancer survivors, persistent local lesions, anatomical deformities secondary to surgical interventions, emotional and mental scaring, and other treatment sequalae increase public health costs. This burden is especially hard on emerging economies.
A device is needed for an accurate, noninvasive, rapid, and low cost method for diagnosing and for treating HPVI, cervical dysplasia, cervical precancer, and cervical cancer.